Molecular sieves of the crystalline aluminosilicate zeolite type are well known in the art and now comprise over 150 species of both naturally occurring and synthetic compositions. In general, the crystalline zeolites are formed from corner-sharing AlO.sub.2 and SiO.sub.2 tetrahedra and are characterized by having pore openings of uniform dimensions, having a significant ion-exchange capacity and being capable of reversibly desorbing an adsorbed phase which is dispersed throughout the internal voids of the crystal without significantly displacing any atoms which make up the permanent crystal structure.
Other crystalline microporous compositions are known which are not zeolitic but which exhibit the ion-exchange and/or adsorption characteristics of the zeolites. These include: (1) a pure silica polymorph, silicalite, having a neutral framework containing neither cations nor cation sites as disclosed in the U.S. Pat. No. 4,061,724; (2) crystalline aluminophosphate compositions disclosed in U.S. Pat. No. 4,310,440; (3) silicon substituted aluminophosphates as disclosed in U.S. Pat. No. 4,440,871 and (4) titanium substituted aluminophosphates as disclosed in U.S. Pat. No. 4,500,651.
All of the crystalline molecular sieves described above are based on the oxide of the metal. It would be very desirable to synthesize crystalline microporous materials based on sulfides and selenides. Since sulfur, unlike oxygen, possesses d electron orbitals of low energy, a great flexibility in configuration is available to sulfur in its bonding with other elements. This flexibility should lead to compositions with unique pore structures which should have novel catalytic and electronic properties. Replacement of oxygen with sulfur or selenium should increase the size of the intracrystalline voids and the micropores and therefore increase the size or amount of the occluded species which can be accommodated in the pore.
The prior art shows that a fair amount of work has been done on metal sulfides and selenides. For example, B. Krebs, "Thio-and Seleno-Compounds of Main Group Elements-Novel Inorganic Oligomers and Polymers", Angew. Chem. Int. Ed. Engl. 22 (1983) 113-134, provides a review of main group thio and seleno compounds such as germanium and tin sulfides. Other reports include: preparation of a Cs.sub.2 As.sub.8 S.sub.13 layered compound by W. S. Sheldrick and J. Kaub, Z. Naturforsch. 40b, 571-573 (1985); preparation of thiohydroxo anions of germanium by B. Krebs and H. J. Wallstab, Z. Naturforsch. 36b, 1400-1406 (1981); and preparation of Cs.sub.2 Sb.sub.2 Se.sub.4 by W. S. Sheldrick and J. Kaub, Z. Anorg. Allg. Chem., 536, 114-118 (1986).
However, all the compounds synthesized to date either have a dense structure, a chain, or a layered structure. There is no report of a crystalline three-dimensional microporous metal sulfide or metal selenide. Applicants are the first to synthesize crystalline three-dimensional microporous metal sulfides. Applicants' crystalline metal sulfides have a three-dimensional microporous framework structure of MS.sub.2 units where M is germanium, tin, or a combination thereof. The crystalline composition has the following empirical formula expressed in molar ratios: xR:MA.sub.2.+-.0.2 :zH.sub.2 O, where A is sulfur or selenium, R represents at least one organic templating agent present in the intracrystalline pore system, x has a value of greater than 0 to about 1, and z has a value from 0 to about 4.
Applicants have also been able to synthesize metal sulfide microporous compounds in which some of the germanium or tin atoms have been replaced with one or more metals. Preferred metals may be selected from the group consisting of cobalt, zinc, manganese, iron, nickel, copper, cadmium and gallium. Again, applicants are the first to have synthesized these compounds. Finally, applicants have found that these crystalline three-dimensional microporous composites exhibit adsorption/desorption properties and exhibit fluorescence showing that this new family of compounds have applications in adsorptive separations, as luminescent display materials and as substrates for luminescent sensors or optrodes. These sulfides may also be used as catalysts or catalyst supports in metal sulfide-based catalysts such as hydrogenation, dehydrogenation, dehydration, hydrotreating and syngas conversion reactions.